<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>focus-whthin</title>
		<style>
			.cs-datalist {
				display: none;
				position: absolute;
				border: 1px solid #ddd;
				background-color: #FFFFFF;
			}
			.cs-datalist a {
				display: block;
				line-height: 2;
				width: 50px;
			}
			.cs-details {
				border: 1px solid black;
				width: fit-content;
			}
			.cs-details:focus-within .cs-datalist {
				display: block;
			}
		</style>
	</head>
	<body>
		<p>focus-within响应该元素，以及其所有子元素的focus事件</p>
		<div class="cs-details">
			<a href="javascript:">点开</a>
			<div class="cs-datalist">
				<a href>1<sup>1</sup></a>	
				<a href>2</a>	
				<a href>3</a>	
				<a href>4</a>	
			</div>
		</div>
	</body>
</html>
